Apple chose to comply that way. We're arguing over poor design right now because this is a user story for no one - that's Apple's fault. There are thousands of ways to comply with the DMA, and the proposed one here is nonsense; Android and Mac exist as proof that you can give people choice without sabotaging them.

Ostensibly, you're right; why give the uninformed masses an imperative browser decision? If Apple was willing to make it optional or put it behind a Developer Mode, they wouldn't be faced with such stark regulation. Blame whoever you want, but the writing has been on the walls for years - Apple sabotaged themselves if they weren't prepared for sideloading.